On Sat, Nov 17, 2012 at 11:19 PM, Agle, Jeff <jeff.agle@financialpartners.com> wrote:
I’m seeing a lot of high latency and packet loss from my Cogent Co. link in MA towards IP 4.2.2.2. Not present on other local ISP. Traces would seem to indicate the problem is at Cogent’s POP to L3. Can anyone confirm, or sympathize?
As discussed many times on here in the past, 4.2.2.2 is a bad (statistically) place to point measurements at. While publicly addressable and pingable, it's sometimes rate-limited. FWIW, I can connect and query the San Jose anycast site just fine. If you're interested in the 4.2.2.2 / 4.2.2.1 resolvers, by all means ping and measure them based on DNS response time. However, if you're just looking for an indication of routing-path health, try measuring other destinations that take similar paths and summarize those points to factor out the behavior of 4.2.2.0/29 hosts. Cheers, jof